1. Field of the Invention
The present invention relates to a plasma processing apparatus for generating plasma and performing an etching treatment and the like on a substrate.
2. Description of the Related Art
In a process manufacturing a semiconductor device and the like, a device for generating plasma in a processing chamber using a high-frequency voltage and performing an etching treatment or a layer forming treatment on a semiconductor substrate (wafer) has been employed, for example. In such a plasma processing apparatus, typically, refrigerant is made to flow in a refrigerant path formed in a mounting table, on which a substrate is mounted, in the processing chamber to make the mounting table to have a desired temperature and adjust the temperature of the wafer mounted on the mounting table (See, for example, Japanese Patent Application Laid-Open No. 2003-347283).
In order to perform a plasma treatment on a wafer, after a wafer is mounted on a mounting table, a processing gas, for example, a processing gas composed of C4F8, O2 and Ar, is supplied to fill the processing chamber as maintaining a predetermined degree of vacuum, and a high-frequency power is applied to generate plasma from the processing gas in the processing chamber. Using this plasma, a plasma treatment such as a dry etching (RIE) treatment is performed on the wafer. In this case, since the temperature of the wafer is increased due to the dry etching treatment, the mounting table is cooled and the heat of the mounting table is transferred to the wafer to cool the wafer. In this cooling of the wafer, a heat transfer gas such as He gas, which has high heat transference, is supplied to the backside of the wafer and the heat transference between the upper surface of the mounting table and the wafer is improved. With this structure, the wafer is efficiently cooled.